DOCSLIB.ORG

Trimorphic Stepping Stones Pave the Way to Fungal Virulence

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Trimorphic Stepping Stones Pave the Way to Fungal Virulence COMMENTARY Trimorphic stepping stones pave the way to fungal virulence Robert J. Bastidas and Joseph Heitman1 Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710 X he fungal kingdom encompasses Pseudohyphal growth Ϸ1.5 million species (1) as di- A verse as single-celled yeasts, pathogens of animals/plants, and Tplant root symbionts. Fungi are eukary- Y Hyphal growth otic, closely aligned with metazoans (2, 3). Animals and fungi diverged Ϸ1 billion years ago; their last common ancestor was unicellular, motile, and aquatic. Some fungi grow as unicellular yeasts, but most B X X are filamentous multicellular organisms. Importantly, some fungi are dimorphic, growing as both yeast and filamentous forms (i.e., Saccharomyces cerevisiae). Yet Fig. 1. Fungal morphological transitions. (A) Yeast undergoes dimorphic transitions to pseudohyphae or others are trimorphic and grow as yeast, hyphae controlled by different elements (X, Y). (B) A continuous transition from yeast to pseudohyphae hyphae, and pseudohyphae (i.e., Candida to hyphae controlled by a dosage-dependent factor (x, X). albicans). S. cerevisiae pseudohyphal growth long eluded detection—it requires special conditions/strains and was lost dur- yeasts (lacking Cph1 and Efg1 transcrip- filaments were observed. When the tet- tion factors or cyclin Hgc1) or filaments UME6 strain was grown as hyphae (doxϪ) ing domestication (4). How pseudohyphae ϩ are related to yeast and hyphae (as a dis- (lacking the Tup1 repressor) are both and then shifted to repress (dox ), filaments tinct fate or a continuum) was unknown avirulent, linking both forms to pathogen- produced a majority of pseudohyphae by 3 h until the report of Carlisle et al. (5)inthis esis (8–10). Subsequently, a strain was and yeast by 7 h. Thus both filamentous issue of PNAS. They reveal that engineered in which morphogenesis is modes can be reversibly evoked by express- pseudohyphae are intermediate between controlled by regulated expression of a ing a single regulatory element in a dosage- yeast and hyphae, with implications for filamentation repressor, Nrg1, with the tet dependent fashion, providing evidence that pathogen–host interactions and fungal promoter (11). Cells grown without doxy- pseudohyphae are intermediate between evolution. cycline express Nrg1 and grow as yeast, yeast and hyphae, rather than a distinct fate. C. albicans is a trimorphic fungus from whereas growth with doxycycline re- When animals were infected with yeast of Ϫ the Ascomycota, diverged from S. cerevisiae pressed Nrg1 and filamentous growth en- the tet-UME6 strain (dox ), increased Ume6 Ϸ200 million years ago (6, 7), and a com- sued. Animals infected with yeast re- expression led to enhanced hyphal growth mensal of the human microbiota of the gas- mained healthy yet harbored a significant and tissue invasion and more rapid demise; trointestinal tract, mucous membranes, and latent fungal burden in the kidney. Add- animals given doxycycline survived much skin. C. albicans infects humans, causing oro- ing doxycycline to drinking water acti- longer. Hence, hyphal growth (or hyphal- pharyngeal disease, vaginitis, and systemic vated filamentation, with progression to specific gene expression) promotes C. albi- life-threatening infection. Serum induces C. lethal infection. These studies provide ro- cans virulence. albicans yeast to produce germ tubes, and bust support for the concept that dimor- The findings of Carlisle et al. (5) have growth in defined media elicits two filamen- phic transitions underlie C. albicans viru- broad implications for dimorphism in fungal tous growth modes: pseudohyphae and hy- lence, and they show that yeast can pathogenesis (Fig. 2). S. cerevisiae and C. phae (Fig. 1A). Pseudohyphae resemble hy- penetrate tissues, whereas hyphae are nec- albicans both undergo yeast–pseudohyphal phae, but are morphologically distinct. In essary for progression to lethal infection. transitions, but only C. albicans develops both modes the normally ovoid yeast cells In cultured macrophages S. cerevisiae is hyphae. As C. albicans evolved into a suc- are elongated, but in pseudohyphae each killed after phagocytosis, whereas C. albi- cessful commensal of the mammalian gastro- cell–cell junction is constricted, and the di- cans yeast switch to hyphae, killing and intestinal tract, formation of hyphae in bio- ameter between cell walls is wider in the escaping macrophages (12). films was likely necessary to compete with middle than the ends. In contrast, hyphal cell The studies of Carlisle et al. (5) involve bacteria, or to form cooperative multispecies walls are parallel with no mother–daughter controlling expression of Ume6, a zinc-finger biofilms (15). Hyphae are also critical for C. or septal junction constrictions. Pseudohy- transcription factor downstream of Nrg1 in albicans to survive and escape host macro- phae and hyphae also differ with respect to circuits for dimorphic transition and viru- phages. As a result, the trimorphic species C. septin localization and nuclear division (7). lence (13, 14). In their studies, Ume6 was albicans is a successful commensal and Given these differences, it has been unclear expressed from the doxycycline-regulatable pathogen, whereas the dimorphic yeast S. whether pseudohyphae are an intermediate promoter (tet-UME6), leading to controlled between yeast and hyphae or are an alterna- consequences: yeast with the promoter off tive fate (Fig. 1). This question, and implica- (doxϩ), and hyphae in response to high-level Author contributions: R.J.B. and J.H. wrote the paper. tions for virulence, were addressed by Carl- Ume6 (doxϪ), even under non-filament- The authors declare no conflict of interest. isle et al. with engineered strains (5). inducing conditions. Intermediate expression See companion article on page 599. The C. albicans dimorphic yeast–hy- elicited a third fate: pseudohyphae. Increas- 1To whom correspondence should be addressed. E-mail: phae transition is thought to underlie its ing Ume6 levels converted pseudohyphae to [email protected]. success as a pathogen. Mutants locked as hyphae, and hybrid hyphal/pseudohyphal © 2009 by The National Academy of Sciences of the USA www.pnas.org͞cgi͞doi͞10.1073͞pnas.0811994106 PNAS ͉ January 13, 2009 ͉ vol. 106 ͉ no. 2 ͉ 351–352 Downloaded by guest on September 24, 2021 envision an ancestral fungus as a unicellular yeast making the leap, first to pseudohyphae and then hyphae. This would have facilitated foraging for mating partners and nutrients and rapid colonization of habitats, including plants/animals. In this model mutations may block just hyphal growth, or hyphal and pseudohyphal growth. Overexpression of other regulatory components may enable dimorphic yeasts to produce hyphae. Most fungi are filamentous with no yeast form, thus mutations preventing the dimorphic return to yeast likely confer selective bene- fits. These studies may provide insights into how closely related species evolved divergent life styles (Fig. 2). S. cerevisiae grows as yeast and pseudohyphae but not hyphae, whereas its close relative Ashbya gossypii grows only as hyphae and Holleya sinecauda grows as yeast, pseudohyphae, and hyphae (22–24). A. gossypii thus lacks functions for hyphal–yeast Fig. 2. Evolution of fungal form and function. Mono-, di-, and trimorphic fungi are shown. transition, and H. sinecauda has factors en- abling hyphal growth from yeast and pseudohyphae. Recent studies reveal that the cerevisiae is an uncommon pathogen (16). iomycota phylum, the plant pathogen Usti- pescadillo ortholog promotes production of Exploring genetic circuits controlling dimor- lago maydis can grow as yeast, but successful budding yeast cells from C. albicans hyphae phism in both species, and those between plant infection requires filamentous dikary- (25), and related factors may enable Crypto- them, is likely to be illustrative. ons produced by mating (20). The human coccus neoformans hyphae to produce yeast The ability of fungi to infect humans oc- pathogen Cryptococcus neoformans under- cells (21). Other fungi, such as Mucor sp. in curred independently multiple times, and goes a similar sexual dimorphic transition, the Zygomycota, prominently grow as fila- successful human pathogens are diverse (Fig. but spores or dried yeast cells infect humans mentous fungi in lab aerobic conditions yet 2). The prominent role for hyphae in C. albi- and only yeast occur in the host (21). Other also grow as multibudded yeasts in anaero- cans virulence is contrasted with a leading fungi infecting plants and humans are strictly bic/high-CO2 conditions (26). Conditions or role for yeast in other pathogens. The di- filamentous. How these diverse pathogenic mutations enabling other filamentous fungi morphic fungal pathogens (i.e., Histoplasma strategies subvert host defenses may share to grow as pseudohyphae or yeast may re- capsulatum) are thermally dimorphic, grow- common principles, or converge via distinct main to be discovered. Understanding ge- ing as filamentous molds at lower environ- mechanisms. netic circuits evoking transitions in fungal mental temperatures and as yeast at 37 °C The findings of Carlisle et al. (5) have form, and impact on biology and infection, (17). Humans are infected by inhaled broader evolutionary implications. The find- will continue to fascinate for years to come. conidia that must convert to yeast to be ing that pseudohyphae are a developmental ACKNOWLEDGMENTS. This work was supported pathogenic. Strains or mutants
Load more

Recommended publications
  • Genome Diversity and Evolution in the Budding Yeasts (Saccharomycotina)
    | YEASTBOOK GENOME ORGANIZATION AND INTEGRITY Genome Diversity and Evolution in the Budding Yeasts (Saccharomycotina) Bernard A. Dujon*,†,1 and Edward J. Louis‡,§ *Department Genomes and Genetics, Institut Pasteur, Centre National de la Recherche Scientifique UMR3525, 75724-CEDEX15 Paris, France, †University Pierre and Marie Curie UFR927, 75005 Paris, France, ‡Centre for Genetic Architecture of Complex Traits, and xDepartment of Genetics, University of Leicester, LE1 7RH, United Kingdom ORCID ID: 0000-0003-1157-3608 (E.J.L.) ABSTRACT Considerable progress in our understanding of yeast genomes and their evolution has been made over the last decade with the sequencing, analysis, and comparisons of numerous species, strains, or isolates of diverse origins. The role played by yeasts in natural environments as well as in artificial manufactures, combined with the importance of some species as model experimental systems sustained this effort. At the same time, their enormous evolutionary diversity (there are yeast species in every subphylum of Dikarya) sparked curiosity but necessitated further efforts to obtain appropriate reference genomes. Today, yeast genomes have been very informative about basic mechanisms of evolution, speciation, hybridization, domestication, as well as about the molecular machineries underlying them. They are also irreplaceable to investigate in detail the complex relationship between genotypes and phenotypes with both theoretical and practical implications. This review examines these questions at two distinct levels offered by the broad evolutionary range of yeasts: inside the best-studied Saccharomyces species complex, and across the entire and diversified subphylum of Saccharomycotina. While obviously revealing evolutionary histories at different scales, data converge to a remarkably coherent picture in which one can estimate the relative importance of intrinsic genome dynamics, including gene birth and loss, vs.
    [Show full text]
  • Introduction to Mycology
    INTRODUCTION TO MYCOLOGY The term "mycology" is derived from Greek word "mykes" meaning mushroom. Therefore mycology is the study of fungi. The ability of fungi to invade plant and animal tissue was observed in early 19th century but the first documented animal infection by any fungus was made by Bassi, who in 1835 studied the muscardine disease of silkworm and proved the that the infection was caused by a fungus Beauveria bassiana. In 1910 Raymond Sabouraud published his book Les Teignes, which was a comprehensive study of dermatophytic fungi. He is also regarded as father of medical mycology. Importance of fungi: Fungi inhabit almost every niche in the environment and humans are exposed to these organisms in various fields of life. Beneficial Effects of Fungi: 1. Decomposition - nutrient and carbon recycling. 2. Biosynthetic factories. The fermentation property is used for the industrial production of alcohols, fats, citric, oxalic and gluconic acids. 3. Important sources of antibiotics, such as Penicillin. 4. Model organisms for biochemical and genetic studies. Eg: Neurospora crassa 5. Saccharomyces cerviciae is extensively used in recombinant DNA technology, which includes the Hepatitis B Vaccine. 6. Some fungi are edible (mushrooms). 7. Yeasts provide nutritional supplements such as vitamins and cofactors. 8. Penicillium is used to flavour Roquefort and Camembert cheeses. 9. Ergot produced by Claviceps purpurea contains medically important alkaloids that help in inducing uterine contractions, controlling bleeding and treating migraine. 10. Fungi (Leptolegnia caudate and Aphanomyces laevis) are used to trap mosquito larvae in paddy fields and thus help in malaria control. Harmful Effects of Fungi: 1.
    [Show full text]
  • Candida Auris
    microorganisms Review Candida auris: Epidemiology, Diagnosis, Pathogenesis, Antifungal Susceptibility, and Infection Control Measures to Combat the Spread of Infections in Healthcare Facilities Suhail Ahmad * and Wadha Alfouzan Department of Microbiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait; [email protected] * Correspondence: [email protected]; Tel.: +965-2463-6503 Abstract: Candida auris, a recently recognized, often multidrug-resistant yeast, has become a sig- nificant fungal pathogen due to its ability to cause invasive infections and outbreaks in healthcare facilities which have been difficult to control and treat. The extraordinary abilities of C. auris to easily contaminate the environment around colonized patients and persist for long periods have recently re- sulted in major outbreaks in many countries. C. auris resists elimination by robust cleaning and other decontamination procedures, likely due to the formation of ‘dry’ biofilms. Susceptible hospitalized patients, particularly those with multiple comorbidities in intensive care settings, acquire C. auris rather easily from close contact with C. auris-infected patients, their environment, or the equipment used on colonized patients, often with fatal consequences. This review highlights the lessons learned from recent studies on the epidemiology, diagnosis, pathogenesis, susceptibility, and molecular basis of resistance to antifungal drugs and infection control measures to combat the spread of C. auris Citation: Ahmad, S.; Alfouzan, W. Candida auris: Epidemiology, infections in healthcare facilities. Particular emphasis is given to interventions aiming to prevent new Diagnosis, Pathogenesis, Antifungal infections in healthcare facilities, including the screening of susceptible patients for colonization; the Susceptibility, and Infection Control cleaning and decontamination of the environment, equipment, and colonized patients; and successful Measures to Combat the Spread of approaches to identify and treat infected patients, particularly during outbreaks.
    [Show full text]
  • Basidiomycete Mycelia in Forest Soils: Dimensions, Dynamics and Roles in Nutrient Distribution
    Mycol. Res. 109 (1): 7–20 (January 2005). f The British Mycological Society 7 DOI: 10.1017/S0953756204001753 Printed in the United Kingdom. Review Basidiomycete mycelia in forest soils: dimensions, dynamics and roles in nutrient distribution John W. G. CAIRNEY Centre for Horticulture and Plant Sciences, University of Western Sydney, Parramatta Campus, Locked Bag 1797, Penrith South DC, NSW 1797, Australia. E-mail: [email protected] Received 15 July 2004; accepted 3 October 2004. Basidiomycete mycelia are ubiquitous in forest soils where they fulfil a range of key ecological functions. Population studies, based largely on basidiome collections, indicate that mycelia of many ectomycorrhizal and saprotrophic basidiomycetes can spread vegetatively for considerable distances through soil, but the extent to which these become physically or physiologically fragmented is unclear. This review considers aspects of the distribution, dynamics and translocatory activities of individual basidiomycete mycelia in forest soil, highlighting current gaps in our understanding and possible ways to address these. INTRODUCTION in soil have been constrained by a lack of suitable techniques for discrimination between them, but some On the basis of basidiome collections, it is evident that progress is now being made. A useful method for esti- forest soils in a broad range of habitats house diverse mating ECM mycelial biomass in forest soils has, for communities of basidiomycetes (e.g. Schmit, Murphy example, recently been developed (Wallander et al. & Mueller 1999, de la Luz Fierros, Navarrete-Heredia 2001). This involves burying mesh bags containing & Guzma´n-Davalos 2000, Ferris, Peace & Newton sand in forest plots and comparing mycelial biomass in 2000, Packham et al.
    [Show full text]
  • Candida Species Identification by NAA
    Candida Species Identification by NAA Background Vulvovaginal candidiasis (VVC) occurs as a result of displacement of the normal vaginal flora by species of the fungal genus Candida, predominantly Candida albicans. The usual presentation is irritation, itching, burning with urination, and thick, whitish discharge.1 VVC accounts for about 17% to 39% of vaginitis1, and most women will be diagnosed with VVC at least once during their childbearing years.2 In simplistic terms, VVC can be classified into uncomplicated or complicated presentations. Uncomplicated VVC is characterized by infrequent symptomatic episodes, mild to moderate symptoms, or C albicans infection occurring in nonpregnant and immunocompetent women.1 Complicated VVC, in contrast, is typified by severe symptoms, frequent recurrence, infection with Candida species other than C albicans, and/or occurrence during pregnancy or in women with immunosuppression or other medical conditions.1 Diagnosis and Treatment of VVC Traditional diagnosis of VVC is accomplished by either: (i) direct microscopic visualization of yeast-like cells with or without pseudohyphae; or (ii) isolation of Candida species by culture from a vaginal sample.1 Direct microscopy sensitivity is about 50%1 and does not provide a species identification, while cultures can have long turnaround times. Today, nucleic acid amplification-based (NAA) tests (eg, PCR) for Candida species can provide high-quality diagnostic information with quicker turnaround times and can also enable investigation of common potential etiologies
    [Show full text]
  • Hypha and Its Characteristics
    Clinical Microbiology: Open Access Commentary Hypha and its Characteristics Giusina Caggiano* Department of Biomedical Sciences, University of Bari, Bari, Italy DESCRIPTION growing tip, dividing the hypha into individual cells. Hyphae can branch by the bifurcation of a growing tip or by the emergence A fungus or actinobacterium's hypha is a long, branching of a new tip from an existing hypha. The behaviour of hypha can filamentous structure. Hyphae are the primary mode of be described as follows: environmental stimuli, such as the vegetative growth and are referred to collectively as a mycelium. application of an electric field, can control the direction of A hypha is made up of one or more cells that are surrounded by hyphal growth. Hyphae can detect reproductive units from afar a tubular cell wall. Most fungi divide their hyphae into cells via and grow towards them. To penetrate a permeable surface, internal cross-walls known as "septa". Septa are typically hyphae can weave through it. Hyphae can be modified in a perforated by pores large enough to allow ribosomes, variety of ways to perform specific functions. Some parasitic mitochondria, and occasionally nuclei to pass between cells. In fungi develop haustoria that aid in absorption within host cells. contrast to plants and oomycetes, which have cellulosic cell walls, Arbuscules of mutualistic mycorrhizal fungi perform a similar the major structural polymer in fungal cell walls is typically function in nutrient exchange and are therefore important in chitin. Some fungi have aseptate hyphae, which mean that their assisting plant nutrient and water absorption. In lichens, hyphae hyphae are not divided by septa.
    [Show full text]
  • 6 Infections Due to the Dimorphic Fungi
    6 Infections Due to the Dimorphic Fungi T.S. HARRISON l and S.M. LEVITZ l CONTENTS VII. Infections Caused by Penicillium marneffei .. 142 A. Mycology ............................. 142 I. Introduction ........................... 125 B. Epidemiology and Ecology .............. 142 II. Coccidioidomycosis ..................... 125 C. Clinical Manifestations .................. 142 A. Mycology ............................. 126 D. Diagnosis ............................. 143 B. Epidemiology and Ecology .............. 126 E. Treatment ............................. 143 C. Clinical Manifestations .................. 127 VIII. Conclusions ........................... 143 1. Primary Coccidioidomycosis ........... 127 References ............................ 144 2. Disseminated Disease ................ 128 3. Coccidioidomycosis in HIV Infection ... 128 D. Diagnosis ............................. 128 E. Therapy and Prevention ................. 129 III. Histoplasmosis ......................... 130 I. Introduction A. Mycology ............................. 130 B. Epidemiology and Ecology .............. 131 C. Clinical Manifestations .................. 131 1. Primary and Thoracic Disease ......... 131 The thermally dimorphic fungi grow as molds in 2. Disseminated Disease ................ 132 the natural environment or in the laboratory at 3. Histoplasmosis in HIV Infection ....... 133 25-30 DC, and as yeasts or spherules in tissue or D. Diagnosis ............................. 133 when incubated on enriched media at 37 DC. E. Treatment ............................
    [Show full text]
  • Fungi in Bronchiectasis: a Concise Review
    International Journal of Molecular Sciences Review Fungi in Bronchiectasis: A Concise Review Luis Máiz 1, Rosa Nieto 1 ID , Rafael Cantón 2 ID , Elia Gómez G. de la Pedrosa 2 and Miguel Ángel Martinez-García 3,* ID 1 Servicio de Neumología, Unidad de Bronquiectasias y Fibrosis Quística, Hospital Universitario Ramón y Cajal, 28034 Madrid, Spain; [email protected] (L.M.); [email protected] (R.N.) 2 Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain; [email protected] (R.C.); [email protected] (E.G.G.d.l.P.) 3 Servicio de Neumología, Hospital Universitario y Politécnico la Fe, 46016 Valencia, Spain * Correspondence: [email protected]; Tel.: +34-60-986-5934 Received: 3 December 2017; Accepted: 31 December 2017; Published: 4 January 2018 Abstract: Although the spectrum of fungal pathology has been studied extensively in immunosuppressed patients, little is known about the epidemiology, risk factors, and management of fungal infections in chronic pulmonary diseases like bronchiectasis. In bronchiectasis patients, deteriorated mucociliary clearance—generally due to prior colonization by bacterial pathogens—and thick mucosity propitiate, the persistence of fungal spores in the respiratory tract. The most prevalent fungi in these patients are Candida albicans and Aspergillus fumigatus; these are almost always isolated with bacterial pathogens like Haemophillus influenzae and Pseudomonas aeruginosa, making very difficult to define their clinical significance. Analysis of the mycobiome enables us to detect a greater diversity of microorganisms than with conventional cultures. The results have shown a reduced fungal diversity in most chronic respiratory diseases, and that this finding correlates with poorer lung function.
    [Show full text]
  • Oxylipin Distribution in Eremothecium
    1 Oxylipin distribution in Eremothecium by Ntsoaki Joyce Leeuw Submitted in accordance with the requirements for the degree Magister Scientiae in the Department of Microbial, Biochemical and Food Biotechnology Faculty of Natural and Agricultural Sciences University of the Free State Bloemfontein South Africa Supervisor: Prof J.L.F. Kock Co- supervisors: Dr C.H. Pohl Prof P.W.J. Van Wyk November 2006 2 This dissertation is dedicated to the following people: My mother (Nkotseng Leeuw) My brother (Kabelo Leeuw) My cousins (Bafokeng, Lebohang, Mami, Thabang and Rorisang) Mr. Eugean Malebo 3 ACKNOWLEDGEMENTS I wish to thank and acknowledge the following: ) God, to You be the glory for the things You have done in my life. ) My family (especially my mom) – for always being there for me when I’m in need. ) Prof. J.L.F Kock for his patience, constructive criticisms and guidance during the course of this study. ) Dr. C.H. Pohl for her encouragement and assistance in the writing up of this dissertation. ) Mr. P.J. Botes for assistance with the GC-MS. ) Prof. P.W.J. Van Wyk and Miss B. Janecke for assistance with the CLSM and SEM. ) My fellow colleagues (especially Chantel and Desmond) for their assistance, support and encouragement. ) Mr. Eugean Malebo for always being there when I needed you. 4 CONTENTS Page Title page I Acknowledgements II Contents III CHAPTER 1 Introduction 1.1 Motivation 2 1.2 Definition and classification of yeasts 3 1.3 Classification of Eremothecium and related genera 5 1.4 Pathogenicity 12 1.5 Oxylipins 13 1.5.1 Definition
    [Show full text]
  • Hyphal Tip Growth: Outstanding Questions
    Bartnicki-Garcia HYPHAL TIP GROWTH: OUTSTANDING QUESTIONS Salomón Bartnicki-García Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, México and Department of Plant Pathology, University of California, Riverside, California. I. GENERAL 2 II. KEY STRUCTURES AND PROCESSES IN TIP GROWTH 2 A. THE CENTRAL QUESTION - POLARIZED SECRETION.....................................................................................2 B. THE SPITZENKÖRPER .................................................................................................................................3 1. Organizer of vesicle traffic ..................................................................................................................3 2. The Spitzenkörper as a Vesicle supply Center (VSC) .............................................................................4 3. Spitzenkörper Trajectory ......................................................................................................................6 4. Growth Pulses and Satellite Spitzenkörper............................................................................................6 5. Spitzenkörper origin.............................................................................................................................7 6. Questions.............................................................................................................................................7 C. THE CYTOSKELETON .................................................................................................................................8
    [Show full text]
  • Chronic Mucocutaneous Candidiasis Associated with Paracoccidioidomycosis in a Patient with Mannose Receptor Deficiency: First Case Reported in the Literature
    Revista da Sociedade Brasileira de Medicina Tropical Journal of the Brazilian Society of Tropical Medicine Vol.:54:(e0008-2021): 2021 https://doi.org/10.1590/0037-8682-0008-2021 Case Report Chronic mucocutaneous candidiasis associated with paracoccidioidomycosis in a patient with mannose receptor deficiency: First case reported in the literature Dewton de Moraes Vasconcelos[1], Dalton Luís Bertolini[1] and Maurício Domingues Ferreira[1] [1]. Universidade de São Paulo, Faculdade de Medicina, Hospital das Clinicas, Departamento de Dermatologia, Ambulatório das Manifestações Cutâneas das Imunodeficiências Primárias, São Paulo, SP, Brasil. Abstract We describe the first report of a patient with chronic mucocutaneous candidiasis associated with disseminated and recurrent paracoccidioidomycosis. The investigation demonstrated that the patient had a mannose receptor deficiency, which would explain the patient’s susceptibility to chronic infection by Candida spp. and systemic infection by paracoccidioidomycosis. Mannose receptors are responsible for an important link between macrophages and fungal cells during phagocytosis. Deficiency of this receptor could explain the susceptibility to both fungal species, suggesting the impediment of the phagocytosis of these fungi in our patient. Keywords: Chronic mucocutaneous candidiasis. Paracoccidioidomycosis. Mannose receptor deficiency. INTRODUCTION “chronic mucocutaneous candidiasis and mannose receptor deficiency,” “chronic mucocutaneous candidiasis and paracoccidioidomycosis,” Chronic mucocutaneous
    [Show full text]
  • The Lifecycle of a Mushroom
    WEB TUTORIAL 21.1 The Lifecycle of a Mushroom Text Sections Section 21.3 Reproduction in Fungi, p. 354 Introduction Mushrooms have an unusual life cycle. After spores are released from mature fruit- ing bodies, they germinate to form hyphae. Collectively, the hyphae make up a branching web, called a mycelium. Hyphae derived from the spores of two differ- ent mating types then fuse to become one cell with two distinct nuclei. Thus begins a phase of life that is unique to fungi: the dikaryotic phase, in which cells in a fun- gal mycelium have two nuclei. This tutorial illustrates the relationships among these phases in the life cycle of a mushroom. Learning Objectives • Know the structures involved in each stage of a mushroom’s life cycle. • Understand why the life cycle of fungi is unique in the tree of life. Narration The Life Cycle of a Mushroom A mushroom is a member of a group of fungi called the Basidiomycota. Let's con- sider its life cycle, beginning with the spores that are produced by the mature fruit- ing body. A spore germinates, dividing by mitosis to produce a filament called a hypha. The hypha grows and branches to produce a filamentous network called a mycelium. The mycelium has a high surface-area-to-volume ratio, which allows the fungus to absorb nutrients efficiently. If the hyphae of different mating types meet, they are attracted to each other and fuse, forming a cell with two nuclei. This is an unusual condition for a cell; in the normal case, one cell has one nucleus.
    [Show full text]